Moisture is known to cause warping, cracking, buckling, rotting and other damage to wood building materials and can create an environment for the growth of mold, mildew and termites in or on the wood. Such moisture may come up from under a building structure from ground water, through the sides, top and bottom from precipitation and directly out of the air as condensation. Moisture and condensation have been a particular problem in building structures having radiant heating systems, since frequent cycling on and off of the radiant heating systems causes moisture condensation around the radiant heating systems. Various types of barriers to moisture and condensation have been developed to prevent damage to the building structures, particularly to wood flooring systems in the building structures.
Many moisture and condensation prevention and/or barrier techniques have been attempted. However, particularly for flooring systems that have a radiant heating system, an appropriate material that provides a sufficient moisture and condensation barrier and that does not degrade over time or with repeated heating and cooling or with exposure to moisture has not been discovered. Additionally, the moisture and condensation barrier techniques typically require complicated and time-consuming installation procedures.
Barrier materials that have been tried include a flexible sheet (single-ply or multi-ply) that is laid (with or without adhesive) between layers of the building structure, such as between layers of the flooring system. The sheet may be made of a polymeric sheet, thermoplastic film, a polymer film, polyethylene, polyvinylchloride, polyurethane, polypropylene, a vinyl film and the like.
Other attempted barrier materials have included a liquid that is placed on top of or sprayed or painted on the side of one or more of the layers of the building structure and allowed to form into a solid. For example, a water based adhesive, synthetic resin film, polymeric layer, polyolefin, polyethylene, polypropylene, polybutylene, polyvinylchloride, hot mastic asphalt tar, thermoplastic elastomers, styrene, butadiene, copolymers and the like may be coated on top of one of the layers and allowed to cool, dry or cure into a vapor or moisture barrier.
Other barrier materials have been formed into boards (typically with wood and typically laminated) that can be used in constructing some of the layers of the building structure. For example, one or more layers or a sheath or envelope of plastic, thermoplastic, thermoplastic resinous polymers, thermoplastic resins, thermoplastic homopolymers, copolymers, copolyester, terpolymers, vinyl resins, polyvinyl, polyvinyl chloride, polyethylene, polypropylene, polyolefins, polyamides, polyurethane, acrylonitrilebutadiene, acrylic resins, phenolic resins, asphalt impregnated fabric, waxes, vulcanized rubber, vulcanizable rubber or rubber latex (vulcanized or heat-pressed in situ), chlorinated rubber, a methyl methacrylate monomer, a hydroxy alkylacrylate or diacetone acrylamide monomer, a chlorinated hydrocarbon, an antimony compound, a zinc compound and the like may be formed on or in the board. Such coated or laminated boards may be used for the subfloor or the finished floor of the flooring system.
Additionally, coated wood boards for building materials have been developed for purposes other than for moisture barriers. For example, rubber particles have been heat pressed onto a wood board to form a board with a non-skid surface. Additionally, pulverized rubber has been added to styrene acrylate polymers and polyvinyl acetate-acrylic co-polymers and sprayed onto a wood board and allowed to cure to form a resilient and skid resistant surface on the board. Additionally, a rubber based elastomeric material has been heat-pressed onto a laminated board and used to bond the laminated board to a substrate coated with a similar rubber based material.
An exemplary prior art building structure 100 is shown in FIG. 1 as having an exemplary prior art flooring system 102 supported by structural joists, or trusses, 104 which in turn are supported by some type of concrete slab 106 so as to elevate the structural joists 104 and flooring system 102 above the ground 108. The prior art flooring system 102 in this example includes a “finished” hardwood floor 110 above a first wood subfloor 112, which overlays an optional radiant heating system 114 above a second wood subfloor 116, which is supported by the structural joists 104. There are many types of radiant heating systems for flooring, but in this example the optional radiant heating system 114 includes lightweight concrete sections 118 having heat pipes 120 displaced throughout the length of the lightweight concrete sections 118. The radiant heating system 114 keeps the flooring system 102, and consequently the building structure 100, warm during cold temperature seasons.
With or without the radiant heating system 114, moisture and condensation commonly reaches the flooring system 102 through the ground 108 or through the concrete slab 106. The radiant heating system 114 commonly exacerbates the moisture and condensation problem. At least one type of flooring system (not shown) is known to incorporate a waterproof sheet or moisture sealing layer (not shown) under the radiant heating system 114, but this placement of the waterproof sheet cannot solve the problem of condensation around the radiant heating system 114 reaching the wood subfloor 112 and the finished hardwood floor 110.
The moisture and condensation problem is also present in building structures that have concrete slabs that do not elevate the flooring system above the ground, but support the flooring system directly on the ground. In such a building structure, a flooring system was formed on top of a concrete slab supported on the ground. The concrete slab also had a radiant heating system built into it. The flooring system was constructed with 30-lb felt tar paper overlaying the radiant heating concrete slab, a layer of plywood placed over the felt tar paper, a layer of glue troweled over the plywood and a finished hardwood floor fastened to the plywood by the glue and staples. Within a year, the flooring system had warped and buckled, due to moisture, which the felt tar paper and the glue layer could not prevent passing from the radiant heating concrete slab to the plywood and the finished hardwood floor. The flooring system was replaced with a second flooring system constructed with a moisture-resistant two-part epoxy squeegeed over the radiant heating concrete slab followed by the plywood, glue and stapled finished hardwood floor. Within half a year, the second flooring system had also warped and buckled and the epoxy had cracked, flaked and separated from the radiant heating concrete slab, due to moisture.
It is with respect to these and other background considerations that the subject matter herein has evolved.